The proposed research will study the mechanism by which the araC gene protein of the L-arabinose operon of Escherichia coli positively and negatively regulates the operon. This will be done on the promoters which serve the genes for active transport of arabinose into the cells. The studies will be done with DNAse footprinting and DNA and RNA sequencing to determine the binding properties and mode of action of the regulatory proteins. Large numbers of regulatory region mutations will be isolated in order to damage the system in known ways so as to provide additional data on the mechanism of action of gene regulation.